1. Field of the Invention
The instant invention is directed to a method for activating a methanol synthesis catalyst while the catalyst is dispersed in an inert liquid. More specifically, the instant invention is directed to a method for activating a methanol synthesis catalyst, the catalyst dispersed as a slurry, in-situ in a liquid phase methanol synthesis reactor.
2. Background of the Prior Art
The synthesis of methanol by the catalytic reaction of synthesis gas is an old and well established chemical process. In this process, carbon monoxide and hydrogen are catalytically reacted to form methanol. The catalyst employed usually comprises a mixture of metal oxides. As those skilled in the art are aware, metal oxides are metals having a high oxidation valence state, in which state the metals are stable. However, the metals are effective as methanol synthesis catalysts at lower oxidation states.
To convert the metal oxides to a catalytically active state, effective for use in a methanol synthesis process, requires reduction of the metal oxides to these more active lower oxidation valence states. This, in the prior art, relating to methanol synthesis in a liquid fluidized or slurry reactor system was usually accomplished by contacting the metal oxide catalyst particles with hydrogen gas, in a controlled manner, in a fixed bed reactor whereby the metal oxides were reduced by removal of oxygen as water. This reaction is highly exothermic, requiring that it be carried out very slowly to avoid the development of excess temperature which could result in sintering of the metals and the concomitant reduction in catalyst activity.
Not only are the methods in the prior art for activating methanol synthesis catalysts for use in liquid fluidized or slurry reactor difficult, but, in addition, they do not provide for the possibility of continuous methanol synthesis processing. That is, in the prior art the activation step is conducted in a reactor separate and distinct from the methanol synthesis gas reactor.
A corollary disadvantage in the distinct and separate steps of activating the catalyst and synthesizing methanol lie in the requirement for at least separate gas streams for activation and methanol synthesis. The use of separate gas streams adds difficulty and expense to the overall methanol synthesis reaction.
U.S. Pat. Nos. 3,888,896 and 4,031,123, each assigned to the assignee of the instant application, disclose the use of methanol synthesis catalyst dispersed in an inert liquid as a slurry employed in the catalytic synthesis reaction to form methanol. The disclosure in these patents is limited to providing an active catalyst, in slurry, in the methanol synthesis reaction. No disclosure is made of activating the catalyst in this state.